The nose wheel of an aircraft landing gear assembly is mounted at the end of a shock absorber strut and is steerable when the aircraft is on the ground. A self-centering mechanism is provided which operates to hold the wheel in the straight-ahead condition when the strut is in the extended unloaded condition, particularly during take-off and landing, and which operates to release the wheel for steering when the strut is retracted/loaded with the aircraft on the ground.
Nose wheel landing gear assemblies have to be tested during development so as to ensure that they will withstand the torques and loads which they experience in operation, and therefore a test rig has to be set up to simulate the steering torques involved. A torque actuator is provided which is connected via a torque cell to a lower portion of the landing gear assembly so as to apply a steering torque to the assembly. However, before the steering torque can be applied to the assembly, the shock absorber strut needs to be retracted so as to release the wheel centering mechanism to allow steering movements. This is achieved by depressurizing the strut and lifting the lower end of the assembly using winches. The torque actuator is then installed and connected via the torque cell to the lower end of the strut before the strut is repressurised so that it is then in the operational loaded state. The torque actuator is then able to apply a torque to the assembly at the required torque levels for the purposes of testing.
An object of the invention is to provide an improved method and apparatus for testing an aircraft nose wheel landing gear.